Denmark's talismanic skipper Pernille Harder found the net three times in her side's 2-0 Women's World Cup Group D victory over Haiti on Tuesday but if there was any disappointment that two of those goals were disallowed the forward did not show it.

The scoreline in Perth ensures, for the first time since 1995, Denmark's passage to the knockout stage where a date awaits in Sydney with co-hosts Australia on Monday.

"It's a long time since we came here, first of all to qualify for a World Cup but now we're also playing the round of 16," the 30-year-old told reporters.

"It's big for us and that's why I'm so proud of the whole team but, of course, we're hungry for more."

The Matildas, fresh off a 4-0 demolition of Olympic champions Canada, present the sternest test yet for Lars Sondergaard's team, who beat China but fell short against Group D table-toppers England.

"We have played Australia twice in the last couple of years, and Sam Kerr played in both of those games," the Denmark coach said, acknowledging the threat posed by the Australia captain, returning from injury.

"So we know how to deal with her, even though it's difficult."

It was a sentiment shared by Harder, a former team mate of Kerr's at Chelsea.

"I've been lucky to play with her for two years, she's an amazing player and an amazing person. I look forward to seeing her but not playing against her," said Harder.

"She's a great striker, she knows where the goal is and she has some unbelievable skills with her headers, that's for sure."

The Danes can take heart from the impeccable form of their own captain, who earned her maiden World Cup goal with a 21st minute penalty against Haiti.

A cheeky half-volley into the net was quickly ruled out due to an offside just before halftime but the VAR reversal of Harder's 85th minute header was more controversial.

Denmark forward Signe Bruun fouled Haiti goalkeeper Kerly Theus' outside the box and amidst the chaos substitute Mille Gejl's cross from the right was guided home by Harder.

"Too bad for Pernille," Sondergaard quipped. "It could have been a goal but she's a team player. It's nice for her to score but I think it's much nicer for her that we came through."